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Field inspection manual—volumetric measuring devices

Specialised test procedure—procedure for testing liquified petroleum gas bulk meters using a vapour displacement prover

Application

This test is applied to liquified petroleum gas (LPG) bulk metering systems.

Purpose

This procedure covers the total inspection of a bulk meter for liquefied gases using a vapour displacement prover.

Legislative references

262, R.263 and R.268 (1) and (2).

Correction factors, subscripts and other variable definitions

Ctl
Correction for the temperature of the liquid
Cpl
Correction for the pressure on the liquid
Cps
Correction for the pressure on the steel
Cts
Correction for the temperature of the steel
Pe
Equilibrium Vapour Pressure
IVp
Indicated Volume in the Prover
IVm
Indicated Volume in the Meter
Tp
Temperature of liquid in the prover
Tm
Temperature of liquid in the meter
Pp
Pressure in the prover
Pm
Pressure in the meter
CVm
Corrected meter volume
CVp
Corrected prover volume

Procedure

Preliminary preparation

  1. Locate the prover away from traffic (if possible) and near power outlet.
  2. Ground the prover to a suitable ground point and to other equipment involved in the test (e.g., truck under test for mobile meters, or being used to return test product).
  3. Level the prover.
  4. Connect power supply and check if pump is operational.
  5. Connect the liquid return line to fitting on supply tank (liquid fill connection).
  6. Connect the delivery line from meter to prover inlet.
  7. Open all valves slowly in the following sequence:
    • Truck vapour line valve
    • Hose vapour line valve
    • Prover vapour return valve
    • Prover liquid return valve
    • Liquid return line valve on hose
    • Truck liquid loading valve
    • Truck liquid delivery valve on hose
    • Prover liquid valve (where truck delivery hose hooks up)
  8. Have truck driver open all other truck valves that would normally be open during regular deliveries (i.e., emergency shut-off, vapour release vent line, pump by-pass, etc.).

    Note: Prover inlet discharge and bleeder valves remain closed at this time. If any leaks occur, close valves immediately and correct the problem.

  9. For Neptune and Brooks meters, remove automatic temperature compensation (ATC) cover and disengage ATC (put pin in uncompensated position).
  10. Partly fill thermometer well with light oil or antifreeze and insert thermometer. If there is more than one thermometer well, use the one in the strainer.
  11. Engage truck power take off (or start supply pump) and check for leaks and creeping of meter.

Preliminary test run(s)

  1. Wet the prover. This is to wet the prover and stabilize its temperature. The listed drain times are not applicable.
  2. Check pressure difference between prover and supply tank during and after each run. If significant pressure difference occurs, the cause must be located and the condition corrected.
  3. Check the temperature at the meter and at the prover. If there is more than 1.5°C difference between the two temperatures then empty the prover and refill.
  4. Pump product back to supply tank.
  5. When the product is below bottom gauge glass, close discharge valve and shut off prover pump.

Performance test

  1. Start supply pump or power take off. Open prover inlet valve to bring liquid level to slightly above zero. Close inlet valve and open prover bleeder valve to lower product level exactly to the zero line.
  2. Set the register to zero.
  3. Perform the minimum tests listed in the applicable inspection procedure outline (IPO) (at least one slow and one fast run).
  4. When making test runs, open the vapour line after some pressure has built up in the prover. This prevents liquid from coming back through the vapour return lines.
  5. Establish meter flow rate.
  6. Take temperature readings at the measuring chamber at four points during each test run.
  7. Take pressure readings at the measuring chamber for each test run.
  8. Take final indicated volume by the register at the end of each run.
  9. Turn supply pump off or have power take off disengaged immediately after the end of the run.
  10. After each run, record the prover volume, average temperature and pressure when the vapour spinner stops.
  11. For each run determine the corrected metered volume or CVm by applying Cplm and Ctlm corrections to the registered meter volume, based on the recorded temperatures and pressures.
  12. For each run determine the corrected prover volume or CVp by applying Cplp, Ctlp, Cpsp and Ctsp corrections to the recorded prover volumes, based on the recorded temperatures and pressures.

    Note: For vapour displacement provers, Cps is determined by testing at time of calibration. A chart or a formula is provided with the inspection certificate for the prover.

    Note: For Cts, since these provers are normally made of steel, use the formula:

    Cts = 1 +   Tp - 15 × 0.0000335

    The vale 0.0000335 is the cubical coefficient of thermal expansion for steel in the système international d'unités (SI) units (Ω/Ω/°C), therefore Tp must be measured in °C.

    Note: For Cpl, follow American Petroleum Institute (API) standard chapter 11.2.2M to establish this factor. See Tables 3a, 3b and 3c below for propane at 500, 505, and 510 kg/m3.

    Note: For Ctl, use ASTM-IP table 54 to determine the appropriate VCF (Volume Correction Factor) for the average observed temperature during the test run in the test well or the measured temperature in the prover. See Table 2 below for Ctl values for propane at 500, 505, and 510 kg/m3.

  13. For each run determine the over or under registration error as follows:

    % Error registration =   CV m -   CV p CV p × 100 %

  14. Check agreement between registrations.

Equilibrium vapour pressure for light hydrocarbons (kPa absolute)

Vapour pressure (Pe) at temperature (T) for LPG with a density of 500, 505, and 510 kg/m³ at 15°C
Temp (°C) 500 kg/m³ (kPa abs) 505 kg/m³ (kPa abs) 510 kg/m³ (kPa abs)
-10 450.1 384.4 328.4
-9 464.2 397.0 339.6
-8 478.6 409.9 351.1
-7 493.4 423.1 362.9
-6 508.5 436.7 375.0
-5 524.0 450.5 387.4
-4 539.8 464.7 400.1
-3 555.9 479.3 413.2
-2 572.4 494.1 426.5
-1 589.3 509.3 440.2
0 606.5 524.9 454.2
1 624.1 540.8 468.6
2 642.1 557.0 483.3
3 660.5 573.7 498.3
4 679.2 590.7 513.7
5 698.3 608.0 529.4
6 717.8 625.7 545.5
7 737.7 643.9 562.0
8 758.0 662.4 578.8
9 778.7 681.3 596.0
10 799.8 700.5 613.6
11 821.3 720.2 631.6
12 843.3 740.3 649.9
13 865.6 760.8 668.7
14 888.4 781.7 687.9
15 911.6 803.1 707.4
16 935.3 824.8 727.4
17 959.4 847.0 747.8
18 983.9 869.6 768.6
19 1008.9 892.7 789.8
20 1034.3 916.2 811.5
21 1060.2 940.1 833.6
22 1086.6 964.5 856.2
23 1113.4 989.4 879.2
24 1140.6 1014.7 902.6
25 1168.4 1040.4 926.5
26 1196.6 1066.7 950.9
27 1225.3 1093.4 975.7
28 1254.5 1120.6 1001.0
29 1284.2 1148.3 1026.8
30 1314.4 1176.5 1053.1
31 1345.1 1205.2 1079.8
32 1376.2 1234.3 1107.0
33 1407.9 1264.0 1134.8
34 1440.1 1294.2 1163.0
35 1472.8 1324.8 1191.8
36 1506.0 1356.0 1221.0
37 1539.8 1387.8 1250.8
38 1574.0 1420.0 1281.1
39 1608.8 1452.8 1311.9
40 1644.1 1486.1 1343.3

Note:

  • Pe values (in kPa absolute) for LPG at 500, 505, and 510 kg/m3 at 15°C
  • Values derived from API chapter 11, section 2, part 2
  • kPa absolute = kPa gauge + 101.325
  • kPa gauge = kPa absolute – 101.325
Liquid temperature correction factors (Ctl) for propane with a density of 500, 505, and 510 kg/m3 at 15°C
Temp (°C) 500 (kg/m3) 505 (kg/m3) 510 (kg/m3)
-15.0 1.0835 1.0818 1.0799
-14.5 1.0822 1.0805 1.0787
-14.0 1.0809 1.0793 1.0774
-13.5 1.0796 1.0780 1.0761
-13.0 1.0783 1.0767 1.0749
-12.5 1.0769 1.0754 1.0736
-12.0 1.0756 1.0741 1.0724
-11.5 1.0743 1.0728 1.0711
-11.0 1.0730 1.0715 1.0698
-10.5 1.0717 1.0702 1.0686
-10.0 1.0703 1.0689 1.0673
-9.5 1.0690 1.0676 1.0660
-9.0 1.0677 1.0663 1.0647
-8.5 1.0663 1.0650 1.0635
-8.0 1.0650 1.0637 1.0622
-7.5 1.0637 1.0624 1.0609
-7.0 1.0623 1.0611 1.0596
-6.5 1.0610 1.0597 1.0583
-6.0 1.0596 1.0584 1.0570
-5.5 1.0583 1.0571 1.0557
-5.0 1.0569 1.0558 1.0544
-4.5 1.0556 1.0544 1.0531
-4.0 1.0542 1.05391 1.0518
-3.5 1.0528 1.0518 1.0505
-3.0 1.0515 1.0504 1.0492
-2.5 1.0501 1.0491 1.0479
-2.0 1.0487 1.0477 1.0466
-1.5 1.0473 1.0464 1.0453
-1.0 1.0460 1.0450 1.0440
-0.5 1.0446 1.0437 1.0426
0.0 1.0432 1.0423 1.0413
0.5 1.0418 1.0410 1.0400
1.0 1.0404 1.0396 1.0386
1.5 1.0390 1.0382 1.0373
2.0 1.0376 1.0369 1.0360
2.5 1.0362 1.0355 1.0346
3.0 1.0348 1.0341 1.0333
3.5 1.0334 1.0327 1.0319
4.0 1.0320 1.0314 1.0306
4.5 1.0306 1.0300 1.0292
5.0 1.0292 1.0286 1.0279
5.5 1.0277 1.0272 1.0265
6.0 1.0263 1.0258 1.0252
6.5 1.0249 1.0244 1.0238
7.0 1.0235 1.0230 1.0224
7.5 1.0220 1.0216 1.0210
8.0 1.0206 1.0202 1.0197
8.5 1.0191 1.0187 1.0183
9.0 1.0177 1.0173 1.0169
9.5 1.0162 1.0159 1.0155
10.0 1.0148 1.0145 1.0141
10.5 1.0133 1.0130 1.0127
11.0 1.0119 1.0116 1.0113
11.5 1.0104 1.0102 1.0099
12.0 1.0089 1.0087 1.0085
12.5 1.0074 1.0073 1.0071
13.0 1.0060 1.0058 1.0057
13.5 1.0045 1.0044 1.0043
14.0 1.0030 1.0029 1.0029
14.5 1.0015 1.0015 1.0014
15.0 1.0000 1.0000 1.0000
15.5 0.9985 0.9985 0.9986
16.0 0.9970 0.9971 0.9971
16.5 0.9955 0.9956 0.9957
17.0 0.9940 0.9941 0.9942
17.5 0.9925 0.9926 0.9928
18.0 0.9909 0.9911 0.9913
18.5 0.9894 0.9896 0.9899
19.0 0.9879 0.9881 0.9884
19.5 0.9863 0.9866 0.9870
20.0 0.9848 0.9851 0.9855
20.5 0.9832 0.9836 0.9840
21.0 0.9817 0.9821 0.9825
21.5 0.9801 0.9805 0.9810
22.0 0.9786 0.9790 0.9796
22.5 0.9770 0.9775 0.9781
23.0 0.9754 0.9760 0.9766
23.5 0.9739 0.9744 0.9751
24.0 0.9723 0.9729 0.9736
24.5 0.9707 0.9713 0.9720
25.0 0.9691 0.9697 0.9705
25.5 0.9675 0.9682 0.9690
26.0 0.9659 0.9666 0.9675
26.5 0.9643 0.9650 0.9659
27.0 0.9627 0.9635 0.9644
27.5 0.9611 0.9619 0.9629
28.0 0.9594 0.9603 0.9613
28.5 0.9578 0.9587 0.9598
29.0 0.9562 0.9571 0.9582
29.5 0.9545 0.9555 0.9566
30.0 0.9529 0.9539 0.9551
30.5 0.9512 0.9522 0.9535
31.0 0.9496 0.9506 0.9519
31.5 0.9479 0.9490 0.9503
32.0 0.9462 0.9474 0.9487
32.5 0.9445 0.9457 0.9472
33.0 0.9429 0.9441 0.9455
33.5 0.9412 0.9424 0.9439
34.0 0.9395 0.9407 0.9423
34.5 0.9377 0.9391 0.9407
35.0 0.9360 0.9374 0.9391
Table 2:
  • Ctl values for LPG at 500, 505, and 510 kg/m3 at 15°C
  • From ASTM-IP Petroleum Measurement Tables for Light Hydrocarbon Liquids, Table 54, April 1986

Liquid pressure correction factors (Cpl) for propane with a density of 500, 505, and 510 kg/m3 at 15°C

Note: Ensure that Pm and Pe are expressed in the same unit (i.e., kPa absolute or kPa gauge)

Density at 15°C = 500 kg/m3
ΔPress Pm –Pe (kPa) ΔPress Pm –Pe (psi) Tm Temp (°C) -20 to -15.1 Tm Temp (°C) -15 to -10.1 Tm Temp (°C) -10.0 to -5.1 Tm Temp (°C) -5.0 to -0.1 Tm Temp (°C) 0.0 to 4.9 Tm Temp (°C) 5.0 to 9.9 Tm Temp (°C) 10.0 to 14.9 Tm Temp (°C) 15.0 to 19.9 Tm Temp (°C) 20.0 to 24.9 Tm Temp (°C) 25.0 to 29.9 Tm Temp (°C)30.0 to 34.9 Tm Temp (°C) 35.0 to 39.9
50 7.3 1.00016 1.00017 1.00018 1.00020 1.00022 1.00024 1.00027 1.00030 1.00033 1.00037 1.00042 1.00048
100 14.5 1.00031 1.00034 1.00037 1.00040 1.00044 1.00048 1.00053 1.00059 1.00066 1.00075 1.00084 1.00096
150 21.8 1.00047 1.00051 1.00055 1.00060 1.00066 1.00072 1.00080 1.00089 1.00099 1.00112 1.00126 1.00144
200 29.0 1.00062 1.00067 1.00073 1.00080 1.00088 1.00096 1.00107 1.00118 1.00132 1.00149 1.00168 1.00192
250 36.3 1.00078 1.00084 1.00092 1.00100 1.00109 1.00120 1.00133 1.00148 1.00165 1.00186 1.00210 1.00239
300 43.5 1.00093 1.00101 1.00110 1.00120 1.00131 1.00144 1.00160 1.00177 1.00198 1.00222 1.00251 1.00286
350 50.8 1.00109 1.00118 1.00128 1.00140 1.00153 1.00168 1.00186 1.00207 1.00231 1.00259 1.00293 1.00333
400 58.0 1.00124 1.00134 1.00146 1.00159 1.00175 1.00192 1.00212 1.00236 1.00263 1.00296 1.00334 1.00380
450 65.3 1.00139 1.00151 1.00164 1.00179 1.00196 1.00216 1.00238 1.00265 1.00296 1.00332 1.00375 1.00427
500 72.5 1.00155 1.00168 1.00182 1.00199 1.00218 1.00239 1.00265 1.00294 1.00328 1.00368 1.00416 1.00473
550 79.8 1.00170 1.00184 1.00200 1.00219 1.00239 1.00263 1.00291 1.00323 1.00360 1.00404 1.00457 1.00519
600 87.0 1.00186 1.00201 1.00218 1.00238 1.00261 1.00287 1.00317 1.00352 1.00392 1.00441 1.00497 1.00565
650 94.3 1.00201 1.00218 1.00236 1.00258 1.00282 1.00310 1.00343 1.00380 1.00425 1.00476 1.00538 1.00611
700 101.5 1.00216 1.00234 1.00254 1.00277 1.00304 1.00334 1.00369 1.00409 1.00457 1.00512 1.00578 1.00657
750 108.8 1.00231 1.00251 1.00272 1.00297 1.00325 1.00357 1.00394 1.00438 1.00488 1.00548 1.00619 1.00703
800 116.0 1.00247 1.00267 1.00290 1.00316 1.00346 1.00381 1.00420 1.00466 1.00520 1.00584 1.00659 1.00748
850 123.3 1.00262 1.00284 1.00308 1.00336 1.00367 1.00404 1.00446 1.00495 1.00552 1.00619 1.00698 1.00793
900 130.5 1.00277 1.00300 1.00326 1.00355 1.00389 1.00427 1.00472 1.00523 1.00584 1.00654 1.00738 1.00838
950 137.8 1.00292 1.00316 1.00344 1.00375 1.00410 1.00450 1.00497 1.00552 1.00615 1.00690 1.00778 1.00883
1000 145.0 1.00307 1.00333 1.00361 1.00394 1.00431 1.00474 1.00523 1.00580 1.00646 1.00725 1.00817 1.00928
1050 152.3 1.00323 1.00349 1.00379 1.00413 1.00452 1.00497 1.00548 1.00608 1.00678 1.00760 1.00857 1.00972
1100 159.5 1.00338 1.00365 1.00397 1.00432 1.00473 1.00520 1.00574 1.00636 1.00709 1.00795 1.00896 1.01016
1150 166.8 1.00353 1.00382 1.00414 1.00452 1.00494 1.00543 1.00599 1.00664 1.00740 1.00829 1.00935 1.01060
1200 174.0 1.00368 1.00398 1.00432 1.00471 1.00515 1.00566 1.00624 1.00692 1.00771 1.00864 1.00974 1.01104
Table 3a:
  • Cpl values for propane at 500 kg/m3 at 15°C
  • From API CHAPTER 11.2.2M)
Density at 15°C = 505 kg/m3
ΔPress Pm –Pe (kPa) ΔPress Pm –Pe (psi) Tm Temp (°C) -20 to -15.1 Tm Temp (°C) -15 to -10.1 Tm Temp (°C) -10.0 to -5.1 Tm Temp (°C) -5.0 to -0.1 Tm Temp (°C) 0.0 to 4.9 Tm Temp (°C) 5.0 to 9.9 Tm Temp (°C) 10.0 to 14.9 Tm Temp (°C) 15.0 to 19.9 Tm Temp (°C) 20.0 to 24.9 Tm Temp (°C) 25.0 to 29.9 Tm Temp (°C)30.0 to 34.9 Tm Temp (°C) 35.0 to 39.9
50 7.3 1.00015 1.00016 1.00018 1.00019 1.00021 1.00023 1.00025 1.00028 1.00031 1.00035 1.00040 1.00045
100 14.5 1.00030 1.00033 1.00035 1.00038 1.00042 1.00046 1.00051 1.00056 1.00063 1.00070 1.00079 1.00090
150 21.8 1.00045 1.00049 1.00053 1.00058 1.00063 1.00069 1.00076 1.00085 1.00094 1.00106 1.00119 1.00135
200 29.0 1.00060 1.00065 1.00070 1.00077 1.00084 1.00092 1.00102 1.00113 1.00125 1.00141 1.00158 1.00180
250 36.3 1.00075 1.00081 1.00088 1.00096 1.00105 1.00115 1.00127 1.00141 1.00157 1.00175 1.00198 1.00224
300 43.5 1.00090 1.00097 1.00106 1.00115 1.00126 1.00138 1.00152 1.00169 1.00188 1.00210 1.00237 1.00268
350 50.8 1.00105 1.00113 1.00123 1.00134 1.00146 1.00161 1.00177 1.00196 1.00219 1.00245 1.00276 1.00312
400 58.0 1.00120 1.00129 1.00140 1.00153 1.00167 1.00184 1.00202 1.00224 1.00249 1.00279 1.00315 1.00356
450 65.3 1.00135 1.00146 1.00158 1.00172 1.00188 1.00206 1.00227 1.00252 1.00280 1.00314 1.00353 1.00400
500 72.5 1.00149 1.00162 1.00175 1.00191 1.00209 1.00229 1.00252 1.00279 1.00311 1.00348 1.00392 1.00444
550 79.8 1.00164 1.00178 1.00193 1.00210 1.00229 1.00252 1.00277 1.00307 1.00342 1.00382 1.00430 1.00487
600 87.0 1.00179 1.00194 1.00210 1.00229 1.00250 1.00274 1.00302 1.00334 1.00372 1.00416 1.00469 1.00530
650 94.3 1.00194 1.00210 1.00227 1.00247 1.00270 1.00297 1.00327 1.00362 1.00403 1.00450 1.00507 1.00574
700 101.5 1.00209 1.00226 1.00245 1.00266 1.00291 1.00319 1.00352 1.00389 1.00433 1.00484 1.00545 1.00617
750 108.8 1.00223 1.00241 1.00262 1.00285 1.00311 1.00342 1.00376 1.00416 1.00463 1.00518 1.00583 1.00659
800 116.0 1.00238 1.00257 1.00279 1.00304 1.00332 1.00364 1.00401 1.00444 1.00493 1.00552 1.00620 1.00702
850 123.3 1.00253 1.00273 1.00296 1.00322 1.00352 1.00386 1.00425 1.00471 1.00524 1.00585 1.00658 1.00744
900 130.5 1.00267 1.00289 1.00313 1.00341 1.00373 1.00408 1.00450 1.00498 1.00554 1.00619 1.00696 1.00787
950 137.8 1.00282 1.00305 1.00331 1.00360 1.00393 1.00431 1.00474 1.00525 1.00583 1.00652 1.00733 1.00829
1000 145.0 1.00297 1.00321 1.00348 1.00378 1.00413 1.00453 1.00499 1.00552 1.00613 1.00685 1.00770 1.00871
1050 152.3 1.00311 1.00336 1.00365 1.00397 1.00433 1.00475 1.00523 1.00579 1.00643 1.00719 1.00808 1.00913
1100 159.5 1.00326 1.00352 1.00382 1.00415 1.00454 1.00497 1.00547 1.00605 1.00673 1.00752 1.00845 1.00955
1150 166.8 1.00341 1.00368 1.00399 1.00434 1.00474 1.00519 1.00572 1.00632 1.00702 1.00785 1.00881 1.00996
1200 174.0 1.00355 1.00384 1.00416 1.00452 1.00494 1.00541 1.00596 1.00659 1.00732 1.00818 1.00918 1.01037
Table 3b:
  • Cpl values for propane at 505 kg/m3 at 15°C
  • From API CHAPTER 11.2.2M)
Density at 15°C = 510 kg/m3
ΔPress Pm –Pe (kPa) ΔPress Pm –Pe (psi) Tm Temp (°C) -20 to -15.1 Tm Temp (°C) -15 to -10.1 Tm Temp (°C) -10.0 to -5.1 Tm Temp (°C) -5.0 to -0.1 Tm Temp (°C) 0.0 to 4.9 Tm Temp (°C) 5.0 to 9.9 Tm Temp (°C) 10.0 to 14.9 Tm Temp (°C) 15.0 to 19.9 Tm Temp (°C) 20.0 to 24.9 Tm Temp (°C) 25.0 to 29.9 Tm Temp (°C)30.0 to 34.9 Tm Temp (°C) 35.0 to 39.9
50 7.3 1.00015 1.00016 1.00017 1.00018 1.00020 1.00022 1.00024 1.00027 1.00030 1.00033 1.00037 1.00042
100 14.5 1.00029 1.00031 1.00034 1.00037 1.00040 1.00044 1.00049 1.00054 1.00060 1.00067 1.00075 1.00085
150 21.8 1.00043 1.00047 1.00051 1.00055 1.00060 1.00066 1.00073 1.00080 1.00089 1.00100 1.00112 1.00127
200 29.0 1.00058 1.00063 1.00068 1.00074 1.00080 1.00088 1.00097 1.00107 1.00119 1.00133 1.00149 1.00169
250 36.3 1.00072 1.00078 1.00085 1.00092 1.00100 1.00110 1.00121 1.00134 1.00149 1.00166 1.00186 1.00210
300 43.5 1.00087 1.00094 1.00102 1.00110 1.00120 1.00132 1.00145 1.00160 1.00178 1.00199 1.00223 1.00252
350 50.8 1.00101 1.00109 1.00118 1.00129 1.00140 1.00154 1.00169 1.00187 1.00207 1.00232 1.00260 1.00293
400 58.0 1.00116 1.00125 1.00135 1.00147 1.00160 1.00175 1.00193 1.00213 1.00237 1.00264 1.00297 1.00335
450 65.3 1.00130 1.00140 1.00152 1.00165 1.00180 1.00197 1.00217 1.00240 1.00266 1.00297 1.00333 1.00376
500 72.5 1.00144 1.00156 1.00169 1.00183 1.00200 1.00219 1.00241 1.00266 1.00295 1.00329 1.00369 1.00417
550 79.8 1.00159 1.00171 1.00185 1.00201 1.00220 1.00241 1.00265 1.00292 1.00324 1.00362 1.00406 1.00458
600 87.0 1.00173 1.00187 1.00202 1.00220 1.00239 1.00262 1.00288 1.00318 1.00353 1.00394 1.00442 1.00499
650 94.3 1.00187 1.00202 1.00219 1.00238 1.00259 1.00284 1.00312 1.00344 1.00382 1.00426 1.00478 1.00539
700 101.5 1.00201 1.00217 1.00235 1.00256 1.00279 1.00305 1.00336 1.00370 1.00411 1.00458 1.00514 1.00580
750 108.8 1.00216 1.00233 1.00252 1.00274 1.00298 1.00327 1.00359 1.00396 1.00440 1.00490 1.00550 1.00620
800 116.0 1.00230 1.00248 1.00269 1.00292 1.00318 1.00348 1.00383 1.00422 1.00468 1.00522 1.00585 1.00660
850 123.3 1.00244 1.00263 1.00285 1.00310 1.00338 1.00370 1.00406 1.00448 1.00497 1.00554 1.00621 1.00700
900 130.5 1.00258 1.00279 1.00302 1.00328 1.00357 1.00391 1.00429 1.00474 1.00526 1.00586 1.00657 1.00740
950 137.8 1.00272 1.00294 1.00318 1.00346 1.00377 1.00412 1.00453 1.00500 1.00554 1.00618 1.00692 1.00780
1000 145.0 1.00286 1.00309 1.00335 1.00363 1.00396 1.00433 1.00476 1.00525 1.00583 1.00649 1.00727 1.00819
1050 152.3 1.00301 1.00324 1.00351 1.00381 1.00416 1.00455 1.00499 1.00551 1.00611 1.00681 1.00762 1.00859
1100 159.5 1.00315 1.00340 1.00368 1.00399 1.00435 1.00476 1.00523 1.00577 1.00639 1.00712 1.00797 1.00898
1150 166.8 1.00329 1.00355 1.00384 1.00417 1.00454 1.00497 1.00546 1.00602 1.00667 1.00743 1.00832 1.00937
1200 174.0 1.00343 1.00370 1.00400 1.00435 1.00474 1.00518 1.00569 1.00627 1.00695 1.00774 1.00867 1.00976
Table 3c:
  • Cpl values for propane at 510 kg/m3 at 15°C
  • From API CHAPTER 11.2.2M)
Example 1:

Determine the equilibrium vapour pressure Pe for 510 kg/m3 Propane

The average temperature at test well during proving run is: 18.6°C

  1. Using Table 1 above, we note that the equilibrium vapour pressure Pe is:
    • Pe = 768.6 kPa absolute at 18°C
    • Pe = 789.8 kPa absolute at 19°C
  2. Interpolating between the two temperatures, the Pe at 18.6°C is calculated as:

    Pe = 768.6 + 789.8 - 768.6 19 - 18 × 18.6 - 18 = 781.32 kPa absolute

  3. Convert Pe value from kPa absolute to kPa gauge

    Pe gauge = Pe absolute – 101.325 = 781.32 – 101.325 = 680 kPa gauge

Example 2:

Determine the liquid pressure correction factor Cpl.

The measured flowing pressure at the meter is 1210 kPa gauge.

  1. Calculate the pressure difference between the flowing pressure and the equilibrium vapour pressure.
    Gauge pressure at the meter:
    1210 kpa gauge
    Vapour pressure from example 1:
    680 kpa gauge
    Difference:
    530 kpa
  2. Enter Table 3c (density of 510 kg/m3) in the column for 15 to 19.9°C (since the average temperature was 18.6°C). Move down vertically to the nearest corresponding pressure difference shown in the left hand column to determine the proper Cpl. In this case:
    • Cpl = 1.00266 at a pressure differential of 500 kPa
    • Cpl = 1.00292 at a pressure differential of 550 kPa
  3. Interpolate between the two Cpl values to determine the correct Cpl.

    Cpl = 1.00266 + 1.00292 - 1.00266 550 - 500 × 530 - 500 = 1.00282

Example of a test run

Prover data

Vapour Displacement

Nominal Volume = 380 litres

Material = Steel

Cps = 1 + (Psi gauge reading × 0.000007666)

Note: 1 kPa = 0.145038 Psi
Reference Temperature = 15°C

Test run data

IVp =
378.75 litres
Tp =
3.8 °C
Pp =
450 kPa gauge

Calculations

Ctlp @ 3.8°C from ASTM-IP table 54 = 1.0311

Pep @ 3.8°C from Table 1 = 510.6 kPa abs

PpPe = (450+101.3) − 510.6 = 40.7 kPa abs

Cplp from Table 3c = 1.0002

Ctsp = 1+ (3.8 − 15) 0.0000335 = 0.9996

Cpsp = 1+ (450 kPa × 0.145038 psi/kPa × 0.000007666) = 1.0005

CVp = IVp × Ctlp × Cplp × Ctsp × Cpsp
378.75 × 1.0311 × 1.0002 × 0.9996 × 1.0005

CVp = 390.64 litres

Measuring system data:

1.5 inch Neptune measuring element

SWA 636 Rev. 1

Min 45 to 228 max L/min

Vehicle mounted

Liquid Controls register, Model LC III

SWA: 2188 r-5

Test run data

IVm gross =
379.3 litres
IVm net =
391.3 litres
Avg. Tm =
3.4°C
Pm =
1200 kPa gauge
Flow rate =
165 L/min

Calculations

Ctlm @ 3.4°C from ASTM-IP table 54 = 1.0322

Pem @ 3.4°C from Table 1 = 504.5 kPa abs

PmPe = (1200 + 101.3) – 504.5 = 796.8 kPa abs

Cplm from Table 3c = 1.0032

CVm = IVm × Ctlm × Cplm
379.3 × 1.0322 × 1.0032

CVm = 392.77 litres

In terms of registration, the % error is calculated as:

% Error registration =   CV m -   CV p CV p × 100 % =   392.77 - 390.64 390.64 × 100 = 0.54 % over registration

Check of the automatic temperature compensation (ATC) feature

Net/Gross = 391.3 / 379.3 = 1.0316 and, therefore,

The Corresponding Temperature = 3.6°C

Temperature error = 3.4 − 3.6 = -0.2°C

Revisions

Revision 1

The purpose of this revision was to have the test procedure revised to better explain the required pressure and temperature corrections involved; added definitions section and supplemental procedure with charts to illustrate alternative method to use when determining the Cpl (correction for the pressure on the liquid) factor. Examples added to illustrate the calculation processes.

Revision 2

The purpose of this revision is to:

  • Revised Equilibrium Vapour Pressure (Pe in kPa absolute) Chart 1 to include densities of 500, 505 and 510 kg/m3 propane.
  • Added table1 with Pe values (in kPa absolute) for 500, 505 and 510 kg/m3 propane.
  • Added table 1 with Pe values (in kPa absolute) for 500, 505, and 510 kg/m3 propane.
  • Added table 2 with Ctl values for 500, 505, and kg/m3 propane.
  • Added table 3a with Cpl values for 500 kg/m3 propane.
  • Added table 3b with Cpl values for 505 kg/m3 propane.
  • Added table 3c with Cpl values for 510 kg/m3 propane.
  • Updated example calculations.
Date modified: